Method of forming a textile member with undulating wire

ABSTRACT

A method of forming a textile having an undulating wire member therein. The method includes forming a wire which exhibits shape memory behavior into an undulating wire member, training the wire to remember its shape, causing the undulating wire member to straighten by undergoing a shape-memory transformation, securing the straightened wire member in a conventional textile and then causing the straightened wire to undergo a shape memory transformation back to the remembered undulating shape.

This is a division of copending application Ser. No. 09/437,875, filedNov. 10, 1999, which is a division of copending application Ser. No.09/134,192, filed Aug. 14 1998.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method of forming a textile, and moreparticularly, to a method of forming a textile having therein anundulating wire member which exhibits shape memory behavior.

2. Brief Description of the Prior Art

Vascular graft techniques have been known for approximately 30 years.Knitted or woven tubes are formed from fibrous materials and areemployed to repair a damaged body tube, such as a damaged vascularstructure. Patients with diseased or damaged vascular structures, orother body tubes, can be successfully treated with such graftstructures. For example, a patient with an abdominal aortic aneurysm canhave the aneurysm repaired with a suitable graft. However, pure graftstructures, although designed to enhance fluid integrity of the damagedbody tube, do not have the capability to support themselves or to besecured in place. Thus, invasive surgery is required to attach thestructures to the damaged vascular area, which may result in a long,expensive hospital stay and attendant dangers due to the major surgeryrequired.

In an effort to overcome the problems with graft structures, analternative approached was developed in the early 1980s. So-calledstents were developed which could expand a clogged artery, for example,and be self-securing by virtue of an interference fit with the arterywall. Such structures might be self-expanding, by virtue of recovery ofelastic stress, or might be formed of ductile materials and expandedwith a balloon catheter. However, so-called stent structures do not inthemselves enhance the fluid integrity of the body tube. They rely onthe diseased wall of the body tube to maintain fluid integrity, and aredirected primarily to expanding the body tube such as, for example, aclogged artery.

Recently, devices have been developed which combine the benefits of bothgraft and stent structures. In these types of devices, a stent structureis secured to a graft structure. The graft structure serves to enhancefluid integrity of the body tube, while the stent structure helps tosupport the graft and to secure the graft in place against the bodytube. These types of devices can be implanted with a catheter procedure,and thus do not require invasive surgery.

U.S. Pat. No. 4,130,904 to Whalen, U.S. Pat. No. 4,313,231 to Koyamada,U.S. Pat. No. 5,507,767 to Maeda et al., U.S. Pat. No. 5,591,195 toThaeri et al., U.S. Pat. No. 5,667,523 to Bynon et al., and U.S. Pat.No. 5,674,277 to Freitag all disclose combined stent/graft structures.Although these structures have significantly enhanced patient treatment,a number of problems still remain. Heretofore, most combined stent/graftstructures have fastened the stent to the graft via suturing or glue.These methods are problematic. Suturing may not be repeatable forquality control, can be unreliable, resulting in potential loosening ofthe stent from the graft, with catastrophic results for the patient, andmay degrade fluid integrity of the graft due to the needle holesrequired for the suturing. Gluing may also be unreliable and may poserepeatability and quality control problems as well. U.S. Pat. Nos.5,571,173 and 5,578,071, both to Parodi, show a graft structure with anundulating wire which is woven into the graft. The wire is confined toan end of the graft structure, and is made of a ductile material. Itmust be expanded by a balloon catheterization procedure. The Parodipatents suggest that the stent can be woven into the interior of thegraft, but provide no details as to how this can be accomplished.Further, the undulating wire of Parodi appears to have a global axiswhich is parallel to the fill yarns of the graft, and thus, could not beextended over the whole length of the graft structure.

In view of the deficiencies of prior art devices, it would be desirableto provide a stent/graft structure wherein the stent is integrallysecured to the graft in a manner which does not compromise fluidintegrity, is reliable, and is repeatable for quality control purposes.It would also be desirable if the stent member in the combined structureis secured in a way which lent itself to easy manufacturing. Yetfurther, it would be desirable if a global axis of the stent membercould describe a generally helical path with respect to the graftstructure, such that a single stent member could extend substantiallyover the whole length of the graft, thus providing support throughoutthe length of the graft.

SUMMARY OF THE INVENTION

The present invention, which addresses the needs of the prior art,provides a method of forming a textile with an undulating wire membertherein. The method takes advantage of so-called shape memory materials.The method includes forming a wire which exhibits shape memory behaviorinto an undulating wire member, training the wire to remember its shapewhile it is formed into the undulating wire member, and causing theundulating wire member to straighten by undergoing a shape-memorytransformation, so as to result in a straightened wire which retains amemory of an undulating shape. The method further includes securing thestraightened wire into a conventional textile and then causing thestraightened wire to undergo a shape memory transformation back to theremembered undulating shape.

These and other features and advantages of the present invention willbecome apparent from the following description of the preferredembodiments and the accompanying drawings, and the scope of theinvention will be pointed out in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a stent/graft structure in accordance with the presentinvention;

FIG. 2 shows a cross section through a stent member, including thecentroid thereof;

FIG. 3 shows the formation of an angle between a stent member and anaxis of a graft;

FIG. 4A shows one method of securing a stent member;

FIG. 4B shows another method of securing a stent member;

FIG. 4C shows yet another method of securing a stent member,

FIG. 4D is a view similar to FIG. 4B with texturized stent-securingyarns;

FIG. 5 shows interweaving of a stent member with a woven graft portion;

FIG. 6 shows a first type of bifurcated stent/graft structure;

FIG. 7 shows another type of bifurcated stent/graf structure;

FIG. 8 shows a tapered stent/graft structure;

FIG. 9 shows another type of tapered stent/graft structure;

FIG. 10 shows another bifurcated stent/graft structure with a compositestent;

FIG. 11 shows a structure of the present invention in the process ofinstallation into an aortic aneurysm;

FIG. 12 shows a stent/graft assembly with a non-undulating stent member;

FIG. 13A and FIG. 13B show steps in forming a shape-memory structuralmember;

FIG. 14 depicts formation of a structural member with a first type ofmandrel;

FIGS. 15A and 15B depict formation of a structural member with a secondtype of mandrel;

FIG. 16 shows a fabric, according to the present invention, with a nonundulating structural member therein;

FIGS. 17A-17I show various steps in a manufacturing method according tothe present invention;

FIG. 18 shows a shuttle assembly in accordance with the presentinvention;

FIG. 19 shows another shuttle assembly in accordance with the presentinvention;

FIG. 20 shows an exploded view of yet another shuttle member inaccordance with the present invention and a batten which workscooperatively with the shuttle;

FIG. 21 is similar to FIG. 20 and shows yet another type of shuttle inaccordance with the present invention;

FIG. 22 is a side elevational view of a loom employing multiple shuttlesaccording to the present invention; and

FIGS. 23A-23G show various steps in another manufacturing methodaccording to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference should now be had to FIG. 1, which depicts a stent/graftstructure according to the present invention, designated generally as10. Structure 10 is adapted for repair of a body tube in a living body.The body tube has an inner surface; an example will be set forth below.The combined stent/graft structure 10 includes a textile graft 12 whichis adapted to enhance fluid integrity of the body tube. The language“adapted to enhance fluid integrity of the body tube” is intended todistinguish from pure stent structures which rely on the body tube perse to maintain fluid integrity. The textile graft 12 is not, however,limited to a graft which is fluid-tight in and of itself; somewhatporous textiles which “grow into” the surrounding body tube to enhancefluid integrity are also contemplated. The graft 12 has a generallytubular graft main portion 14. Graft main portion 14 has a graft mainportion axis 16 and first and second graft main portion ends 18, 20respectively. Graft main portion 14 is formed, at least in part, by atleast one graft yarn. The textile graft 12 can be formed in any manner,such as weaving, knitting, or braiding. A plain-woven embodiment isdepicted in FIG. 1, for exemplary purposes. In this case, the at leastone graft yarn could include a plurality of warp yarns 22 and aplurality of fill or weft yarns 24.

Structure 10 also includes a stent which is expandable between a firstposition which permits easy insertion of the stent into the body tubeand a second position wherein the stent presses securely against theinside surface of the body tube. An example will be provided below. Thestent in turn includes a first elongate wire-shaped stent member 26which has both a first stent member global axis and a first stent memberlocal axis.

With reference now to FIG. 2, the first stent member 26 has a localaxis, projecting from the plane of the paper in FIG. 2, which isgenerally defined by the centroids 28 of adjacent cross-sections 30 ofthe first stent member 26. Since the first stent member 26 is depictedas having a relatively small thickness in FIG. 1, the first stent memberlocal axis can be envisioned in FIG. 1 by simply looking at the shape ofthe first stent member 26. The first stent member global axis 32 isgenerally defined by a straight-line curve fit to the first stent memberlocal axis, defined by centroids 28, in a coordinate system which issubstantially coincident with the generally tubular graft main portion14.

The description of locations of yarns and the like with the respect tosuch a coordinate system is known in the art, as set forth, for example,in page 4-13 of the Atkins & Pearce Handbook of Industrial Braidingauthored by Drs. Frank Ko and Christopher Pastore and available fromAtkins & Pearce, 3865 Madison Pike Covington, Ky. 41017 U.S.A.

FIG. 3 shows a plane (the plane of the paper) containing graft mainportion axis 16 and a projection 32′ of global axis 32 into that plane.As can be seen, a non-orthogonal angle θ is formed. At least substantialportions of the global axis 32 will form such a non-orthogonal anglewith the graft main portion axis 16 when projected into the planecontaining the graft main portion axis 16. The first stent member isselected to have material properties which will support the graft 12when the stent is in the second, or expanded, position. The first stentmember 32 can be made of an elastic element, a ductile material, or apolymer or biodegrading polymer. The elastic materials, as discussedbelow, can be self-expanding, while the ductile materials can beexpanded, for example, by balloon catheterization. Suitable ductilematerials can include, for example, stainless steel, elgiloy, or MP 36.Suitable elastic materials can include titanium, nitinol, or elgiloy.Materials suitable for both ductile and elastic applications can havetheir material properties adjusted by annealing, quenching, and thelike, as known to those of skill in the metallurgical arts. All of theforegoing lists of materials are exemplary, and are not to be taken aslimiting. Those of skill in the art will appreciate that any of a widevariety of additional materials can be employed.

As discussed above, and with reference to FIG. 3, the first stent memberglobal axis 32 is generally defined by a straight-line curve fit to thefirst stent member local axis, defined by centroids 28, in a coordinatesystem substantially coincident with the generally tubular graft mainportion 14. Further, at least substantial portions of the first stentmember global axis 32 form a non-orthogonal angle, such as, for example,angle θ, with the graft main portion axis 14 when they are projectedinto a plane containing the graft main portion axis 14. It will beappreciated that angle θ need not be uniform; for example, in someplaces, the global axis 32 may define an orthogonal angle, but ingeneral, it would be desirable for it to be non-orthogonal. In someembodiments, as shown in FIG. 1, the global axis 32 generally forms ahelix. It will be understood that, when projected into a plane, thestent member global axis does not necessarily form a straight line, buta tangent to the projection 32′ can be used to define the non-orthogonalangle. The mathematics of helical, and other functions which are notplane curves is well-known, and can be found, for example, in the bookAdvanced Engineering Mathematics by Erwin Kreyszig, such as at pages374-75 of the 4th Edition published by John Wiley & Sons, Inc. in 1979.

First stent member 32 is integrally secured to textile graft 12 by theat least one graft yarn of which the graft 12 is formed. As set forthabove graft 12 is shown as a plain-weave woven graft for illustrativepurposes.

Reference should now be had to FIGS. 4A, 4B and 4C. As noted, textilegraft 12 can be woven, and can be any kind of weave, including, forexample, a plain weave, a herringbone weave, a satin weave, a basketweave, and the like. With reference to FIG. 4A, a portion of graft 12 isshown as a plain-weave including a plurality of warp yarns 34 and aplurality of fill or weft yarns 36. Fill yarns 36 are substantiallyorthogonal to warp yarns 34. The at least one graft yarn whichintegrally secures the first stent member 26 can be at least one of theplurality of warp yarns 34 and the plurality of fill yarns 36. In oneembodiment, the stent member 26 is secured by at least one of theplurality of warp yarns 34 at an interweave point 38. At present, it isbelieved that weaving with a jacquard head would be desirable whenweaving tubes, in order to obtain warp yarn control to interweave at anypoint around the diameter of the tube.

With reference now to FIG. 4B, if desired, first stent member 26 can besecured by at least two of the warp yarns 34 at each interweave point38.

With reference to FIG. 4C, the plurality of warp yarns 34 can, ifdesired, be divided into a first group of warp yarns 40 and a secondgroup of warp yarns 42. Only a single member of the second group 42 asshown in FIG. 4C, for exemplary purposes. The first group of warp yarns40 would generally not be employed at the interweave points 38 and wouldbe selected for desired properties of the underlying graft 12. Thesecond group of warp yarns 42 would be employed at the interweave points38 and could be selected for desirable properties in securing the firststent member 26. It will be appreciated that desirable properties forthe underlying graft would include control of porosity, strength, andflexibility. Thus, suitable materials for the first group of warp yarns40 would include (but not be limited to) polyester, PTFE, polyglycolicacid (biodegradable applications), and the like. Similar comments applyto the fill yarns. Furthermore, desirable properties for the secondgroup of warp yarns used for securing the stent member 26 would includehigh strength, sealing ability, flexibility, and abrasion resistance.Thus, yarns 42 could have a larger denier than yarns 40, could becomposite yarns, could be textured yarns, or could be made of a strongermaterial. At present, materials such as polyester, PTFE, and the likeare believed preferable for yarns 42.

Textured yarns can be used for any of the warp yarns and/or the fillyarns discussed throughout this application, to enhance fluid integrityat the interweave points. FIG. 4D shows a view similar to FIG. 4Bwherein the yarns designated as 1034 are textured or texturized, toenhance fluid integrity. “Textured” and “texturized” are usedinterchangeably in this application and should be given their ordinarymeaning in the textile arts. One or more texturized yarns 1034 can beemployed; two are shown in FIG. 4D. Bands of fill yarns adjacent theinterweave points could also be texturized. Any of the yarns of thepresent invention can have thicknesses ranging from about 0.0005 inches(about 0.013 mm) to about 0.030 inches (about 0.76 mm), although thisrange is not limiting. Expressed in terms of Denier, yarns for medicalapplications can range, for example, from about 10 Denier to about 80Denier, although this range should not be taken as limiting. Non-medicalapplications, such as industrial filtration and abrasive cloths, can useany desired Denier, for example, up to 1200 Denier or higher. So-calledmicrodenier yarns can be employed, wherein the yarns have a number offilaments greater than the Denier of the yarn. For example, a 50 Deniermicrodenier yarn could have 68 filaments. Microdenier yarns can beemployed to enhance strength and reduce porosity—such yarns tend toflatten out and thus reduce porosity. Microdenier yarns can be employedfor any of the yarns of the present invention.

Note that graft main portion 14 is shown as having a slight curve inFIG. 1. This is for purposes of illustration, to show the flexibility ofthe structure. It will be appreciated that the structure can besubstantially straightened out such that axis 16 would describe asubstantially straight line. This is depicted in FIG. 3.

Referring back to FIGS. 1&3, it will be appreciated that the first stentmember local axis, defined by the centroids 28, defines a plurality ofundulations 44 which extend on first and second sides of the first stentmember global axis 32. Any desirable shape can be used for undulations44. They are shown in FIG. 1 as being substantially sinusoidal. Thus,they can be periodic, but need not be. Furthermore, in addition tosinusoids, so-called “zig-zag” shapes, with a substantially triangularprofile and suitable rounding at the apexes can be employed. Other typesof shapes are known in the art, and are set forth, for example, in U.S.Pat. No. 5,556,414 to Turi and U.S. Pat. No. 5,575,816 to Rudnick etal., the disclosures of both of which are expressly incorporated hereinby reference. It will be appreciated that periodic undulations 44 aresubstantially periodic about the global axis 32 of the first stentmember 26.

As noted above, substantial portions of the first stent member globalaxis 32, in the embodiment being discussed, form a non-orthogonal anglewith the graft main portion axis 16 when projected into a planecontaining the axis 16. When the textile graft 12 is a woven graft, itwill appreciated that it would normally comprise a plurality of warpyarns 22 and a plurality of weft yarns 24 which would be substantiallyorthogonal to the warp yarns 22. In this case, the first stent memberglobal axis 32 would be substantially non-orthogonal to both theplurality of warp yarns 22 and the plurality of weft or fill yarns 24,as shown in FIG. 1.

The non-orthogonal angle θ which the first stent member global axis 32forms with the graft main portion axis 14 can be a helix angle which isselected to permit the first stent member 26 to extend substantiallybetween the first and second graft main portion ends 18, 20 and toobtain substantially homogeneous compressive and flexural properties forthe combined stent/graft structure 10. It is presently believed that anynon-orthogonal helix angle is operative to achieve these goals, with arange of about 10 degrees to about 85 degrees being preferred, and arange of about 45 degrees to about 85 degrees being somewhat morepreferred. A value of about 82 degrees is presently believed to be mostpreferable. As discussed below, the present invention can includeembodiments where the angle θ is 90 degrees, that is, orthogonal, insome or even all locations.

As noted above, the first stent member 26 is generally wire-shaped. Itcan have a circular cross-section, as shown in FIG. 2, or can beelliptical, oblong, or any other desired shape. Diameters of stent andstructural members discussed herein can range from about 0.003 inches(about 0.08 mm) to about 0.035 inches (about 0.9 mm) for medicalapplications, although these values should not be taken as limiting.Thicknesses as large as the order of 0.1 inch (2.5 mm) or more arecontemplated for industrial fabric applications. In one embodiment thestent member 26 is a wire formed from a ductile material which undergoesplastic deformation induced by a separate expanding force in expandingfrom the first position to the second position. The separate expandingforce can come from balloon catheterization, for example, as discussedbelow. If desired, first stent member 26 can be formed from a wire madefrom an elastic material which undergoes substantially elasticdeformation in expanding from the first position to the second position.In this case, the first stent member 26 can expand from the firstposition to the second position at least substantially by stored energywhich is released upon removal of an external constraint, such as asheath, again as discussed below. Suitable materials for both theelastic and ductile cases have been discussed above.

Referring now to FIG. 5, which shows the stent/graft structure 10“unfolded” into a flat plane for convenience in illustration, the firststent member 26 can be secured to the graft portion 12 at a plurality ofinterweave points 38. Stent member 26 can be secured by at least onewarp yarn 22 at each of the interweave points 38, and adjacentinterweave points can be separated by a predetermined number of fillyarns 24 and a predetermined number of warp yarns 22. For illustrativepurposes, in FIG. 5, each interweave point 38 is separated by two warpyarns 22 and by one fill yarn 24. Any desired number can be used; theexample of FIG. 5 is solely for illustrative purposes. It will beappreciated that, for any given shape of stent member 26, thepredetermined number of warp yarns and predetermined number of fillyarns together define a substantially non-orthogonal angle a which thefirst stent member global axis 32 forms with the plurality of warp yarns22 and a complimentary substantially non-orthogonal angle β=90°−α whichthe first stent member global axis 32 forms with the plurality of fillyarns 24.

In another form of the present invention, the stent member can beprovided with a plurality of securing portions which are positionedsubstantially parallel to the warp yarns and the stent member can beintegrally secured to the graft, at a plurality of interweave points, byone or more weft yarns engaging a respective one of the securingportions. Further details will be provided with respect to thediscussion of FIGS. 23A-23G below.

As noted, the present invention can be used to repair a body tube, ofany type, in a living body. One application which is believe to beespecially promising is for the repair of an abdominal aortic aneurysmin a human being. As is well-known, the human aortic artery bifurcatesin the abdominal region. Accordingly, to repair aneurysms in this area,it is desirable to employ a bifurcated stent/graft structure.

Reference should now be had to FIG. 6, which depicts a bifurcatedembodiment of the present invention, designated generally as 10′. Itemsin FIG. 6 which are similar to those in the preceding figures havereceived the same reference character. Structure 10′ includes abifurcated textile graft portion. The textile graft portion includes thegraft main portion 14 as before, and first and second secondary portions46, 48 respectively emanating from the second graft main portion end 20.First and second secondary portions 46, 48 extend from the second graftmain portion end 20 in a substantially fluid-integrity-enhancingfashion. By this, it is meant that the overall structure enhances thefluid integrity of the bifurcated body tube, such as the aorta, intowhich the structure is to be placed. Those of skill in the art willappreciate that this can be achieved by having a substantiallyfluid-tight graft portion, or by having a graft portion which is notfluid tight in and of itself, but which “grows into” the surroundingbody tubes such as to enhance the fluid integrity of the tubes. Firstand second secondary portions 46, 48 are each generally tubular and havefirst and second secondary portion axes 50, 52 respectively. The firstsecondary portion is formed, at least in part, by at least one firstsecondary portion yarn and the second secondary portion 48 is formed, atleast in part, by at least one second secondary portion yarn. Forillustrative purposes, FIG. 6 shows both secondary portions 46, 48 asbeing plain-weave portions similar to the main portion 14, each having aplurality of warp yarns 22 and a plurality of weft or fill yarns 24.

The stent of structure 10′ further comprises a second elongatewire-shaped stent member 54. Second elongate wire-shaped stent member 54has both a second stent member global axis and a second stent memberlocal axis, defined in entirely the same fashion as for the first stentmember 26 discussed above. The second stent member 54 is also integrallysecured to the graft by at least one graft yarn of which the graft isformed. This can be accomplished as discussed above, for the exemplarycase of a plain-weave. Substantial portions of the second stent memberglobal axis, which has been designated 56, form a non-orthogonal anglewith the graft main portion axis 16 when projected into a planecontaining the graft main portion axis 16, as discussed above withrespect to the first stent member. The second stent member 54 hasmaterial properties which are preselected to support the graft when inthe second position, and the local axis of the second stent member isgenerally defined by the centroids 28 of adjacent cross-sections of thesecond stent member, just as shown in FIG. 2 for the first stent member26. The second stent member global axis 56 is generally defined by astraight-line curve fit to the second stent member local axis in acoordinate system which is substantially coincident with the generallytubular graft main portion 14, again, as set forth above with respect tothe first stent member 26.

Still with reference to FIG. 6, it will be seen that both the first andsecond stent members 26, 54 are present in the graft main portion 14.The first stent member 32 is integrally secured to the first secondaryportion 46 by at least one first secondary portion yarn. Substantialportions of the first stent member global axis 32 form a non-orthogonalangle with the first secondary portion axis 46 when projected into aplane containing the first secondary portion axis 46. Again, this issimilar to the description with respect to the tubular graft mainportion 14 set forth above.

Similarly, the second stent member 54 is integrally secured to thesecond secondary portion 48 by the at least one second secondary portionyarn, with substantial portions of the second stent member global axis56 forming a non-orthogonal angle with the second secondary portion axis48 when projected into a plane containing the second secondary portionaxis 48. As shown in FIG. 6, the first and second stent members 26, 54can be axially spaced in the graft main portion 14 and can form asubstantially double helical structure therein.

Reference should now be had to FIG. 7, which depicts an alternativeembodiment of bifurcated stent/graft structure, designated generally as10″. Construction of this embodiment is essentially similar to that ofembodiment 10′, except that the first and second stent members 26, 54are substantially co-extensive in the graft main portion 14.Accordingly, only the first stent member global axis 32 has been shownin the main portion 14, since it would normally be substantiallycoincident with the global axis 56 of the second stent member 54. It isto be understood that by “coincident” or “co-extensive”, it is meantthat the first and second stent members 26, 54 would be very close toeach other or touching.

With reference back to FIG. 1, it will be appreciated that the firststent member 26 can extend substantially from the first graft mainportion end 18 to the second graft main portion end 20. When the stentmember global axis 32 is non-orthogonal to the axis 16 of generallytubular graft main portion 14, the desired extension between the firstand second ends 18, 20 can be achieved with a single stent member,without the need to put multiple stent members in at a plurality oflocations along the axis 16. This can enhance reliability, simplifymanufacturing, and provide support along the entire length of thestent/graft structure. Uniformity of structural and flexural properties(e.g., flexural rigidity) throughout the structure can be achieved.Furthermore, it can provide radiopacity such that the stent/graftstructure can be viewed on a fluoroscope, with x-ray equipment, and thelike.

Throughout the foregoing, main portion 14, first secondary portion 46and second secondary portion 48 have been depicted as having asubstantially constant diameter, with the diameter of the secondaryportions 46, 48 being somewhat less than that of the main portion 14. Itwill be appreciated that any of the portions can be formed in a taperedfashion, if desired.

Reference should now be had to FIG. 8, which shows an embodiment of theinvention 10′″, substantially similarly to that depicted in FIG. 1,except wherein the graft main portion 14 tapers from the first graftmain portion end 18, to the second graft main portion end 20. The taperin FIG. 8 is not “straight,” but is more rapidly tapered in the middleof the main portion 14.

Referring now to FIG. 9, an alternative tapered embodiment of theinvention is depicted, designated as 10 ^(iv). In this case, the graftmain portion 14 also tapers from the first end 18 to the second end 20,but in a more regular or “straight taper” fashion.

Reference should now be had to FIG. 10, which depicts a compositestent/graft structure, designated generally as 10 ^(v), in accordancewith the present invention. The structure 10 ^(v), is essentiallysimilar to the structure depicted in FIG. 6. The first stent member 26can be formed of an elastic material, as set forth above, and can beselected for flexible self-support of the graft main portion 14. Thefirst stent member 26 can extend along the graft main portion 14 but canterminate before reaching at least one of the first and second graftmain portion ends 18, 20. As shown in FIG. 10, for illustrativepurposes, first stent member 26 terminates before reaching first end 18of graft main portion 14.

Structure 10 ^(v) further includes at least a third stent member 58, andcan preferably include a fourth stent member 60 and a fifth stent member62. The third stent member 58 can be formed of a ductile materialselected for apposition of the body tube inner surface by balloonexpansion. The third stent member 58 can be located at the at least oneof the first and second graft main portion ends 18, 20 which the firststent member 26 terminates before reaching. In FIG. 10, this is thefirst end 18, for illustrative purposes. The third stent member 58 canbe integrally secured to the graft by at least one graft yarn of whichthe graft is formed; for example, it can be secured at a plurality ofinterweave points 38 as set forth above. Since stent members 58, 60, 62are preferably selected to be formed of ductile material for appositionof the body tube inner surface, they need not necessarily extend theentire length of the structure 10 ^(v); they can be localized at theends. Thus, members 60, 62 are located at the ends respectively of thefirst and second secondary portions 46, 48. Since these stent members58, 60, 62 need not extend the entire length of the structure, they canhave a global axis which is orthogonal to the respective axes 16, 50,52. They can be secured, for example, as shown in FIG. 5 but, forexample, without any fill yarns 24 between adjacent interweave points38. It will be appreciated that stent members such as 58, 60, 62 can beused in any of the embodiments of the invention, includingnon-bifircated embodiments, in which case, for example, there might beonly a single elastic stent member 26, in which case the third stentmember 58 could be referred to as the second stent member.

In view of the foregoing discussion, it will be appreciated that, insome embodiments of the invention, the stent could simply include afirst elongate wire-shaped stent member 26 having a plurality ofundulations 44, wherein the global axis 32 of the first stent member 26was substantially orthogonal to the axis 16 of the generally tubulargraft main portion 14. In this case, for example, a woven graft such asgraft 12 could be adapted to enhance fluid integrity of the body tube,as set forth above, and could have a generally tubular graft mainportion 14 with a graft main portion axis 16 and first and second graftmain portion ends 18, 20 respectively. The woven graft 12 would beformed from a plurality of warp yarns 22 and a plurality of fill yarns24 substantially orthogonal to the plurality of warp yarns. Note that,in the general case, graft 12 could be any type of a textile graft andcould include knit or braided structures; however, a woven graft isreferred to in this context.

In the immediately preceding case, the stent could include a stent whichwas expandable between a first position permitting easy insertion of thestent into the body tube and a second position where the stent pressedsecurely against the inside surface of the body tube. The stent couldinclude an elongate wire-shaped stent member with a plurality ofundulations, such as, for example, stent member 58 previously depicted.This stent member could be integrally secured to the graft at a firstplurality at interweave points 38′ as shown in FIG. 10. As discussedabove, the member could be secured by at least one warp yarn at each ofthe first plurality of interweave points 38′. The first plurality ofinterweave points could be spaced circumferentially about the graft 12and could be separated from each other by a predetermined number of thewarp yarns 22.

Just as for the embodiments discussed above, where there was anon-orthogonal angle between the stent member global axis 32 and themain portion axis 16, the warp yarns 22 can be divided into a firstgroup of warp yarns 40 which are not employed at the interweave points38′ and a second group of warp yarns designated as 42 which are employedat the interweave points 38′. This is depicted in FIG. 4C. Again, thefirst group of warp yarns can be selected for desired graft properties,and the second group of warp yarns can be selected for desirableproperties in securing the appropriate stent member, all as discussedabove. Alternatively, stent member 58 could be secured by at least twowarp yarns 34, as discussed above, and depicted in FIG. 4B, at each ofthe interweave points 38′.

Still referring to FIG. 10, the first plurality of interweave points 38′could have a first substantially identical axial coordinate measuredwith respect to axis 16, and the stent member 58 could also be securedto the graft at a second plurality of interweave points 38″ having asecond substantially identical axial coordinate measured with respect toaxis 16. The first and second plurality of interweave points 38′, 38″could be separated by a predetermined number of the fill yarns 24.Throughout the foregoing, it will be appreciated that the stent member58, with global axis orthogonal to axis 16 (or members 60, 62 withglobal axes orthogonal to axes 50, 52 respectively), could be the onlystent member(s) employed in the present invention, that is, the presentinvention is not limited to structures wherein there is at least onestent having a non-orthogonal angle between its global axis and the axisof the corresponding graft portion.

In an alternative form of the invention, also optionally with a stentmember global axis substantially orthogonal to the graft main portionaxis, portions of the undulations of the stent member can besubstantially parallel to the warp yarns at a plurality of securingportions, and the first stent member can be integrally secured to thegraft by one or more fill yarns engaging a respective one of saidsecuring portions at a plurality of interweave points otherwise similarto those described above. Refer also to the discussion of FIGS. 23A-23Gbelow.

Reference should now be had to FIG. 11, which depicts a self-expandingstent/graft structure, according to the present invention, beingemplaced in a body tube. For illustrative purposes, FIG. 11 shows ahuman aorta 60 with first and second bifurcations 62, 64 and an innersurface 66. Stent/graft structure 10 includes a wire-shaped stent member26 which is elastic in character and which will expand upon removal ofan external constraint. As shown in FIG. 11, the external constraint canbe provided by a tube 68. The stent is in the first position, permittingeasy insertion of the stent into the body tube (such as aorta 60), whenit is constrained within tube 68. The stent is in the second position,pressing securely against the inside surface 66 of the body tube 60 inthe expanded region when it has emerged from the constraint of tube 68.It will be appreciated that the aorta 60 depicted in FIG. 11 has ananeurysm 70. Surgical techniques for implanting self-expanding stentdevices are well known in the art, for example, as shown in U.S. Pat.No. 5,556,414 to Turi, the disclosure of which is expressly incorporatedherein by reference.

For those cases wherein a balloon-expandable, ductile stent member isemployed, there are also a number of well-known techniques forimplantation, as depicted, for example, in U.S. Pat. No. 4,787,899 toLazarus, U.S. Pat. No. 5,571,173 to Parodi, and U.S. Pat. No. 5,628,783to Quiachon et al. The disclosures of the Lazarus '899, Parodi '173 andQuiachon et al. '783 patents are also expressly incorporated herein byreference. Thus, those of skill in the surgical arts will appreciate anumber of ways in which the stent/graft structures previously disclosedherein can be implanted into a patient.

Reference should now be had to FIG. 12, which depicts another embodimentof the present invention, designated generally as 10 ^(vi). In thiscase, the first stent member 72 has a local axis and a global axis,defined as above, which are substantially coincident; that is, the firststent member is not periodic about its global axis. Once again, anon-orthogonal angle is formed between the global axis of the firststent member 72 (substantially coincident with the member itself asshown in FIG. 12) and the axis 16 of the generally tubular graft mainportion 14. The non-orthogonal angle which can be seen in FIG. 3,wherein 72′ represents the projection of the non-periodic stent member72 into the plane of the axis 16, can be a helix angle which is selectedto permit the stent member 72 to extend substantially between the firstand second graft main portion ends 18, 20 and to obtain substantiallyhomogenous compressive and flexural properties for the combinedstent/graft structure 10 ^(vi). As above, almost any non-orthogonalhelix angle should permit attainment of these desired features; a rangeof about 10 degrees to about 85 degrees is believed to be preferable,with a range of about 45 degrees to about 85 degrees believed to besomewhat more preferable. A value of about 82 degrees is presentlybelieved to be most preferable.

It will be appreciated that, throughout the present application, thestent member is shown on the outside of the graft portion. This locationis believed preferable for manufacturing purposes, but other appropriatelocations are within the scope of the invention.

The present invention also provides a method of forming a textile withan undulating wire member therein. Referring now to FIG. 13A, an initialstep includes forming a wire exhibiting shape memory behavior into anundulating wire member 74. Any suitable shape memory alloy can be used,such as nickel titanium (NiTi) and the like. Suitable shape memoryallies are known in the metallurgical arts, and are discussed, forexample, in U.S. Pat. No. 4,899,543 to Romanelli et al., the disclosureof which is expressly incorporated herein by reference. An additionalstep in the method includes training the wire to remember its shapewhile it is formed into the undulating wire member 74. Methods oftraining shape memory alloys are know in the metallurgical arts, and areset forth, for example, in the Romanelli et al patent. An additionalstep in the method includes causing the undulating wire member 74 tostraighten by undergoing a shape-memory transformation, suggested by thenotation ΔT (as in FIG. 13B), to thereby produce a straightened wire 76with a memory of an undulating shape, as in the undulating wire member74 of FIG. 13A. The straightened wire 76 can then be secured into aconventional textile, such as a plain-weave, using the methods discussedabove, and once it is secured to the textile, it can undergo anadditional shape memory transformation back to the undulating shaperemembered by member 74 in FIG. 13A.

In one form of the method, the step of forming the wire into theundulating wire member 72 can include provision of a flat mandrel 78with a first series of pins 80 spaced substantially equiangularly at afirst radius R₁ . with a spacing angle φ. The flat mandrel 78 can alsohave a second series of pins 82, also spaced substantially equiangularlyat a second radius R₂, also with the spacing angle φ, and with the firstand second series of pins being substantially φ/2 out of phase, as shownin FIG. 14. In this case, the step of forming the undulating wire membercan also include winding a suitable wire 84, of shape memory material,in an interlaced fashion about the pins 80, 82 to produce the undulatingwire member 74. For example, the wire 84 can be wound inwardly about theouter pins 80 and outwardly about the inner pins 82, alternating innerand outer pins, as shown in FIG. 14.

Reference should now be had to FIGS. 15A and 15B. In an alternativemethod, according to the present invention, of forming a textile with anundulating wire member therein, the step of forming the wire exhibitingthe shape memory behavior into the undulating wire member 74 can includethe sub-step of providing a cylindrical mandrel 86 with a first seriesof pins 88, spaced substantially equiangularly, with a spacing angle γ,along a first helical path 92. The first helical path 92 is representedby a plain dashed line. The mandrel 86 can also include a second seriesof pins at 90 spaced substantially equiangularly, also with the spacingangle γ, along a second helical path 94 which has a substantiallyidentical helix angle to the first helical path 92. The second helicalpath 94 is represented by a dash-dotted line. The second helical path 94can be displaced axially a predetermined distance Z from the firsthelical path 92. The first and second series of pins 88, 90 can besubstantially γ/2 out of phase when viewed along an axis 96 of thecylindrical mandrel 86. The angular relationships are best seen in FIG.15B. Note that FIG. 15B is drawn on a slightly smaller scale than isFIG. 15A. When the cylindrical mandrel 86 is employed, the forming stepof the method can also include winding the wire 84 in an interlacedfashion about the pins 88, 90 to produce the undulating wire member 74.For example, the wire 84 can be wound generally downwardly about thefirst series of pins 88 and generally upwardly about the second seriesof pins 90, as depicted in FIG. 15A. Note that the wire 84 is not shownin FIG. 15B, for clarity.

Reference should now again be had to FIG. 5. It will be appreciated thatthe present invention provides a stent/graft structure. However, thetextile from which the stent/graft structure is manufactured can beuseful in its own right for other applications; for example, in the artof industrial filtration. Accordingly, the present invention alsoprovides a woven textile comprising a plurality of warp yarns 22 and aplurality of fill yarns 24 which are substantially orthogonal to theplurality of warp yarns and which form a base fabric with the warpyarns. The textile also includes an elongate wire-shaped structuralmember (represented by wire-shaped stent member 26) which has both astructural member global axis and a structural member local axis,defined as for the stent member 26 above. In this case, the global axisfor the structural member, represented by stent member 26, is defined bya straight-line curve fit to the member local axis in a coordinatesystem which is substantially coplanar with the warp and fill yarns 22,24. This is true in the case when the textile is an ordinary flattextile and is not woven into a tube or the like.

The structural member, represented by stent member 26, is integrallysecured to the base fabric formed from the warp and fill yarns 22, 24 ata plurality of interweave points 38. The member 26 is secured by atleast one warp yarn 22 at each of the interweave points 38, and theadjacent interweave points are separated by a predetermined number offill yarns 24 and a predetermined number of warp yarns 22, as above. Thepredetermined numbers of yarns determine a substantially non-orthogonalangle α between the global axis 32 of the member 26 and the warp yarns24. Also determined is a complimentary substantially non-orthogonalangle β=90°−α, which is formed between the global axis 32 and the fillyarns 24. As shown in FIG. 5, the structural member local axis candefine a plurality of undulations extending on first and second sides ofthe global axis 32. The undulations can be substantially periodic aboutthe structural member global axis 32, as set forth above with respect tothe stent/graft structure per se.

Any of the types of interconnection depicted in FIGS. 4A through FIG. 4Ccan be employed, including the provision of a first group of warp yarnswhich are not employed at the interweave points and which are selectedfor desired base fabric properties, and a second group of warp yarnsemployed at the interweave points and having properties selected forsecuring the structural member. Desirable base fabric properties caninclude those set forth above for the stent/graft structure, and canalso include properties such as controlled porosity and fluidcompatibility in industrial filtration applications. Fabric stiffnesscontrol is also important in such applications, and can be augmentedwith selection of a suitable structural member. Embodiments can beconstructed wherein there is changing flow resistance as a function ofpressure drop, as the media “bows out” and acts like a relief valve.Further, the bowing properties can be controlled with the structuralmember so as to vary the effective pore size to handle differentparticle size ranges, and the like. Greater bowing, with a less stiffstructural member, will tend to stretch the textile and expand thepores. As discussed above, if desired, at least two warp yarns 22 couldbe employed at each of the interweave points 38, for securing the member26.

Reference should now be had to FIG. 16 which shows a similar type ofwoven textile, but one wherein the structural member local axis andstructural member global axis are substantially coincident. For example,this could represent the case of the non-undulating stent member 72,once the stent fabric was “unrolled” and laid out flat. Again, thenon-orthogonal angles α and β are defined as above, and can preferablyrange from approximately 10 degrees to approximately 85 degrees, or morepreferably from about 45 degrees to about 85 degrees. A value of about82 degrees is presently believed to be most preferable. Again, anynon-orthogonal angle can be useful, the indicated ranges are simplythose presently believed to be preferred. Similar ranges are alsopossible for the woven textile using the undulating member, as shown inFIG. 5. Further, from a strict mathematical point of view, withreference to FIG. 16, it will be appreciated that a generally helicalmember when “unrolled” would not necessarily form a straight line in aplane; the comparison to “unrolling” the non-undulating stent/graftdevice discussed above (embodiment 10 ^(vi)) is not completely precise,but is employed for convenience in illustration. Still with reference toFIG. 16, it will be appreciated that the predetermined number of warpyarns between each interweave point is two and the predetermined numberof fill yarns 24 between each interweave point is one; again, this isfor illustrative purposes, and any desired number of warp and fill yarnscan be chosen.

In another form of woven textile according to the present invention, thestructural member can have a plurality of securing portions which arepositioned substantially parallel to the warp yarns, and the structuralmember can be integrally secured to the base fabric, at a plurality ofinterweave points, by one or more fill yarns engaging a respective oneof the securing portions. Refer also to the discussion of FIGS. 23A-23Gbelow.

Reference should now be had to FIGS. 17A-17G which depict a method ofmanufacturing a woven textile having a structural member integrallywoven therein, in accordance with the present invention. The methodincludes the step of providing a plurality of warp yarns 100. The methodfurther includes the step of displacing a first group of the warp yarns100 in a first vertical direction relative to a second group of the warpyarns 100, to create a first shed 102 between the first and secondgroups of warp yarns 100. This is best seen in FIG. 17C, wherein thefirst group of warp yarns has been designated as 104 and the secondgroup of warp yarns has been designated as 106. The method furtherincludes passing a weft insertion shuttle 108 through the first shed102. This passage is performed in a first weft shuttle directionindicated by the arrow emanating from weft insertion shuttle 108, andforms a weft yarn 110.

The method further includes displacing a third group of the warp yarns100 in a second vertical direction relative to a fourth group of thewarp yarns 100, so as to create a second shed 112 between the third andfourth groups of warp yarns. With reference to FIG. 17D, the third groupof warp yarns is designated as 114, and the fourth group of warp yarnsis designated as 116.

The method further includes passing the weft insertion shuttle 108through the second shed 112 in a second weft shuttle direction,indicated by the arrows emanating from weft S shuttle 108 in FIG. 17D,which is opposed to the first weft shuttle direction shown in FIG. 17C,to form an additional weft yarn 110. The aforementioned steps ofdisplacing the first group of warp yarns, passing the weft insertionshuttle through the first shed, displacing the third group of warpyarns, and passing the weft insertion shuttle through the second shedcan be repeated a predetermined number of times to obtain apredetermined number of the weft yarns 110. For example, with referenceto FIG. 17A, the steps have been repeated so as to obtain four weftyarns 110, looking from the bottom of the figure up until the firstinsertion point, to be discussed next.

Once the predetermined number of weft yarns have been inserted, a singlegiven warp yarn 118 can be displaced in one of the first and secondvertical directions, as shown in FIG. 17E, in order to create astructural member receiving gap 120. The displacement of single givenwarp yarn 118 is understood to be relative to the remainder of the warpyarns 100. The method can further include passing a structural memberinsertion shuttle 122 through the structural member receiving gap 120 ina first horizontal direction indicated by the arrows in FIG. 17E inorder to dispense a wire-like structural member 124 into the receivinggap 120. Structural member 124 could be any of the stent type structuresdiscussed above, for example. With reference now to FIG. 17F, the methodcan include replacing the single given warp yarn 118 in order to securethe structural member 124.

The method can further include displacing all of the warp yarns 100 inan identical vertical direction, as best seen in FIG. 17G. Thedisplacement is conducted relative to the structural member insertionshuttle 122. The structural member insertion shuttle 122 can then bepassed back past the warp yarns 100 without interweaving therewith, asalso shown in FIG. 17G. With reference again now to FIG. 17A, it will beappreciated that structural member 124 has now been captured at a firstinterweave point 126. It should be appreciated that the method stepspreviously described can be carried out substantially in the order setforth. Further, the aforementioned displacement of the first group ofyarns; passing of the weft insertion shuttle in the first direction;displacement of the third group of yarns; and passing of the weftshuttle in the second direction can again be repeated to obtain thepredetermined number of weft yarns 110; as discussed above, thepredetermined number is illustrated in FIG. 17A as four.

Further, the steps of displacing the single given warp yarn; passing thestructural member insertion shuttle through the structural memberreceiving gap in the first direction; replacing of the single given warpyarm; displacement of all the warp yarns in the same direction; andreturn of the structural member insertion shuttle can be repeated withanother given single warp yarn 128, as best seen in FIG. 17A. The secondsingle given warp yarn 128 can be spaced from the first single givenwarp yarn 118 by a predetermined distance which, together with thepredetermined number of fill yarns, defines a non-orthogonal angle abetween the structural member 124 and the warp yarns 100, and whichfurther defines a complimentary non-orthogonal angle β=90°−α between thestructural member 124 and the weft yarns 110. This is best seen in FIG.17A.

In the method, the step of providing the warp yarns 100 can includeproviding a first number of ordinary warp yarns selected for basetextile properties and a second number of securing warp yarns, forexample, yarns 118 and 128, which are used to secure the structuralmember 124 and which are preselected for desirable structural securingproperties. The yarns can be selected as discussed above with respect tothe textile.

In the step of displacing the at least single given warp yarn, in orderto create the structural member receiving gap, at least two adjacentwarp yarns can be displaced, and then, they can both be replacedtogether to secure the structural member, such that the structuralmember 124 is secured by both of the adjacent warp yarns. The foregoingis best illustrated in FIGS. 17H and 17I, where the at least twoadjacent warp yarns have been designated as 118′. It will be appreciatedthat the structural member 124 can be dispensed as an undulating member,or as a substantially straight member. Furthermore, when an undulatingmember is employed, it can be placed under sufficient tension, forexample, by the structural member insertion shuttle 122, so as tosubstantially straighten the undulations in order to aid in insertingthe structural member. The method can also, in the step of passing thestructural member insertion shuttle 122 back past the warp yarns 100without interweaving therewith, further include the sub-step of at leastpartially recapturing an unused portion of the structural member 124.This will be discussed and illustrated further below, with respect to aform of shuttle 122 which is adapted to carry out this task.

It should be appreciated that any desired group of the warp yarns 100can constitute the first group which is displaced in the first verticaldirection relative to the second group. Further, any desired group ofthe warp yarns 100 can constitute the third group which is displaced inthe second vertical direction relative to the fourth group. Thus, anydesired weave can be formed, including a plain weave, a satin weave, aherringbone weave, a basket weave, or any other type of weave desired.For illustrative convenience, a plain weave has been shown in thefigures. It will be appreciated that, in order to form a plain weave,the first group of warp yarns displaced in the first vertical direction,that is, yarns 104, can be those of the warp yarns which are oddnumbered, while the second group of warp yarns can be those which areeven numbered. Further, for a plain weave, the third group and the firstgroup will be identical and the fourth group and the second group willbe identical.

Those of skill in the weaving art will appreciate that FIGS. 17A through17I show a two-dimensional representation of the inventive weavingprocess, for illustrative convenience. Weaving of tubular structures iswell-known in the art and the stent member or other structural membercan be interwoven into such structures exactly as shown in the figures,passing the stent member on the back side of the tube for interweavepoints on the back side.

Reference should now be had to FIGS. 23A-23G which depict representativemethod steps of an alternative method, according to the presentinvention, of manufacturing a woven textile having a structural memberintegrally woven therein. The method includes the steps of providing aplurality of warp yarns 3100 and displacing a first group 3104 of thewarp yarns 3100 in a first vertical direction relative to a second group3106 of the warp yarns 3100, in order to create a first shed 3102between the first and second groups of warp yarns 3104, 3106. The firstshed is depicted in FIG. 23C. The method further includes passing a weftinsertion shuttle 3108 through the first shed 3102, in a first weftshuttle direction, suggested by the double arrow in FIG. 23C, so as toform a weft yarn 3110. The method further includes displacing a thirdgroup 314 of the warp yarns 3100 in a second vertical direction relativeto a fourth group 3116 of the warp yarns 3100, so as to create a secondshed 3112 between the third and fourth groups of warp yarns 3114, 3116respectively.

The method can further include passing the weft insertion shuttle 3108through a second shed 3112 in a second weft shuttle direction, suggestedby the double arrow in FIG. 23D, which is opposed to the first weftshuttle direction, to form an additional weft yarn 3110. All of theaforementioned steps can be repeated a predetermined number of times toobtain a predetermined number of weft yarns 3110. It will be appreciatedthat the foregoing description is substantially similar to that setforth above for the first method of manufacturing a woven textile.Referring now to FIG. 23E, once the previous steps have been performed,a structural member insertion shuttle 3122 can be passed across the warpand weft yarns 3100, 3110 in a first horizontal direction, signified bythe double arrow in FIG. 23E, to dispense a wire-like structural member3124. The wire-like structural member 3124 can have a plurality ofrecessed attachment points 4000 which are substantially parallel to thewarp yarns 100, as best seen in FIG. 23A, and which are aligned with oneof the first and second groups 3104, 3106 of warp yarns 3100, as bestseen in FIG. 23E. As shown therein, looking end on, the recessedattachment point 4000 is substantially aligned with the second group3104 of warp yarns 100. Structural member insertion shuttle 3122 can be“parked” (left stationary) for multiple interweaves, if desired, and canbe moved (during tube weaving) as necessary to the “back” side of thetube for interweave points thereon.

Once the preceding step has been performed, one of the aforementionedsteps of passing the weft insertion shuttle through the first shed inthe first weft shuttle direction or through the second shed in thesecond weft shuttle direction can be repeated so as to secure thewire-like structural member 3124, at a given one of the attachmentpoints 4000, with at least one weft yarn 3110. It will be appreciatedthat more than one weft yarn can be employed by simply making multiplepasses with the weft insertion shuttle 108.

Following the preceding steps, the structural member 3124 can bedisplaced away from the warp and weft yarns 3100, 3110 so as to preventany interference with subsequent weaving. This can be carried out, forexample, by suitable control of the structural member 3124 with thestructural member insertion shuttle 3122. Inventive shuttles which canbe employed with the present invention to dispense the structural memberare discussed below. A suitable weft yarn guide, such as elements 140,140′ to be discussed below, can be employed to pick up the structuralmember 3124 and move it out of the way of the weaving process.

At this point, the steps of displacing the first group of yarns withrespect to the second group of yarns, passing the weft insertion shuttlethrough the first shed, displacing the third group of warp yarns withrespect to the fourth group of warp yarns and then passing the weftinsertion shuttle through the second shed can be repeated to againobtain the predetermined number of weft yarns 3110.

Finally, the steps of passing the structural member insertion shuttleacross the warp and weft yarns, securing the wire-like structural memberwith a weft yarn (or yarns), and moving the structural member out of theway of the weaving process can be repeated as needed so as to secure thestructural member at an additional one of the attachment points with atleast an additional given weft yarn which is spaced from the at leastfirst given weft yarn used in the initial securing step by apredetermined number of weft yarns at a location corresponding to apredetermined number of said warp yarns, such that the predeterminednumber of warp yarns and predetermined number of weft yarns togetherdefine a non-orthogonal angle a between a global axis 4002 (defined asabove) of the structural member 3124 and the warp yarns 3100, and acomplimentary non-orthogonal angle β between the global axis 4002 of thestructural member 3124 and the weft yarns 3110. With particularreference to FIG. 23A, it will be appreciated that (in the exampledepicted therein) a first interweave point 3126 is separated from asecond interweave point 4004 by two of the weft yarns 3110 which arelocated between the two of the weft yarns 3110 which are employed tosecure the structural member 3124. Further, the weft yarns which securethe structural member 3124 do so at predetermined locationscorresponding to a predetermined number of the warp yarns 3100. Stillreferring to FIG. 23A, the predetermined number of warp yarns betweenthe first interweave point 3126 and the second interweave point 4004 isfour. Thus, for a known spacing between the warp and between weft yarns,these predetermined number of warp and weft yarns, respectively, definethe aforementioned non-orthogonal angles.

In view of the foregoing discussion with respect to FIGS. 23A-23G, itwill be appreciated that the structural member 3124 could correspond toone of the aforementioned stent members and that the recessed attachmentpoints 4000 could correspond to the aforementioned securing portions ofthe stent member which are positioned substantially parallel to the warpyarns 3100. Thus, one or more of the weft yarns 3110 can engage arespective one of the securing portions, for example, in the form of therecessed attachment points 4000. Further, it will be appreciated thatstructural member 3124 can correspond to an undulating stent and thatportions of the undulations, for example, where the recessed attachmentpoints 4000 are located, can be substantially parallel to the warp yarns3100 and can correspond to the aforementioned plurality of securingportions. Thus, the fill or weft yarns 3110, as noted, can engagerespective ones of the securing portions, for example, in the form ofthe recessed attachment points 4000. Thus, the aforementioned woventextile can include a structural member, such as structural member 3124,with a plurality of securing portions, for example, in the form of therecessed attachment points 4000, which are positioned substantiallyparallel to the warp yarns 3100 and the structural member can beintegrally secured to the base fabric at a plurality of interweavepoints, such as interweave points 3126, 4004 by at least one fill orweft yarm 3110 engaging a respective one of the securing portions ateach of the interweave points.

Reference should now be had to FIG. 18 which depicts a weaving shuttledesignated generally as 130, in accordance with the present invention.Shuttle 130 is employed for dispensing weft yarns, such as yarns 110,when weaving with a loom. Shuttle 130 comprises a main body portion 132which is adapted to move in a transverse direction through a shed, suchas first shed 102, second shed 112, or structural member receiving gap120, formed of warp yarns 100 on the loom. Shuttle 130 further includesa spool 134 mounted for rotation with respect to the main body portion132 about an axis 136 which is substantially perpendicular to thetransverse direction in which the main body portion 132 moves, and whichis substantially parallel to the warp yarns 100. Spool 134 is adapted tostore the weft yarns 110 and to dispense the weft yarns when the mainbody portion 132 moves through the shed. It is to be emphasized that, inthe process described above, an ordinary shuttle can ordinarily beemployed to dispense the weft yarns 110, that is, for use as weftinsertion shuttle 108. Shuttle 130 depicted in FIG. 18 can be employedwith any type of weft yarn, but is especially adapted for dispensing thestructural member, and thus, for use as the structural member insertionshuttle 122. Accordingly, an undulating structural member, which couldbe a stent member, designated as 138, is shown emanating from the spool134. It will be appreciated that structural member 138 would normallyhave a significant portion wound about spool 134 to be dispensed; thisis not shown in FIG. 18 for purposes of clarity. Shuttle 130 can furthercomprise a weft yarn guide 140 which is secured to the main body portion132, for example, through the axis 136, and which is adapted to receiveand guide the weft yarn, such as structural member 138, which isdispensed from the spool 134. Note that the transverse direction inwhich the main body portion 132 moves is suggested by arrows 142 in FIG.18.

The weft yarn guide 140 can include an eyelet 144 which receives theweft yarn, such as structural member 138. The guide 140 can also includea cantilevered portion 146 having first and second ends 148, 150respectively. First end 148 can be secured to the main body portion 132,for example, through the axis 136 and the second end 150 can be securedto the eyelet 144. The eyelet 144 can be dimensioned in a suitablefashion, and can have a suitable coefficient of friction, such that itreceives a first frictional force applied by the weft yarn, such as thestructural member 138, when the weft yarn, such as structural member138, is being dispensed. For example, the eyelet can be made of amaterial such as a ceramic, which has a suitably polished finish. Theeyelet can have dimensions of, for example, about 0.2 inches (about 5.1mm) by about 0.6 inches (about 15 mm). The cantilevered portion 146 canhave a span and a flexural rigidity which are selected such that theweft yarn guide 140 deflects with application of the first frictionalforce and recoils when the first frictional force is removed asdispensing of the weft yarns such as structural member 138 is completed.

The dimensions and coefficient of friction of the eyelet 144 can be suchthat it applies a second frictional force to the weft yarn, such asstructural member 138, as the cantilevered portion 146 recoils, suchthat at least a portion of the weft yarn such as structural member 138is recaptured. Thus, shuttle 130 can be used in carrying out the methoddescribed above wherein a portion of the structural member isrecaptured. The cantilevered portion 146 can be made from an elasticmaterial such as fiberglass, graphite composite, spring steel, multipleleaves of the same or different materials, and the like. It can havedimensions of about ¼ inch (about 6.4 mm) wide and about ⅛ inch (about3.2 mm) thick. The exemplary dimensions are for fiberglass and they canbe adjusted for materials with higher or lower values of Young's modulusto yield a comparable flexural rigidity. It will be appreciated that, asshown, cantilevered portion 146 is bent in a substantially right-angleshape, and thus comprises first and second cantilevered beams joinedwith rotational fixity at the apex of the angle. Any desiredconfiguration can be employed. For the right angle shape, each beam canhave a length of about 1 inch (about 25 mm).

Reference should now be had to FIG. 19 which depicts an alternative formof shuttle 130′ in accordance with the present invention. Componentssimilar to those in FIG. 18 have received the same reference numeralwith a “prime” thereafter. Guide 140′ in the embodiment of FIG. 19 isspring loaded using suitable springs 152 which bias the guide 140′ to adesired position and return it to the desired position once it has beendeflected, for example, by a frictional force applied from thestructural member 138′. When guide 140′ is biased by the externalsprings 152, it need not necessarily have flexural properties, as forthe cantilevered portion 146 in the embodiment of FIG. 18. It will beappreciated that one or more springs 152 can be used and can bepositioned between the guide 140′ and the main body 132′, for example.Further, it will be appreciated that main body 132′ of the embodimentshown in FIG. 19 is substantially D-shaped.

Referring now back to FIG. 18, shuttle 130 can further include ananti-reverse mechanism, designated generally as 154, which permits thespool 134 to rotate in a first rotational sense for dispensing the yarnsuch as structural member 138, but which prevents rotation in a secondrotational sense which is opposite to the first rotational sense, thatis, when the yarn is being at least partially recaptured by the weftyarn guide 140, for example. The anti reverse mechanism can include asuitable stationary gear 156 secured to axis 136 and a suitablespring-loaded pawl 158 which rotates with the spool 134 and engages thegear 156. Of course, the functions of these two components could bereversed, and the gear could instead be attached to the spool 134 withthe pawl 158 mounted to an external structure and fixed with respect tothe main body 132. The anti reverse mechanism 154 can be configured toapply a drag to the spool 134 to prevent the spool from overrunning whenyarn such as structural member 138 is dispensed therefrom. Such a dragcould be provided, for example, by the repeated engagement of the teethof the gear 156 with the pawl 158, as is known, for example, in fishingreels.

Any of the shuttles 130, 130′ can be fitted with a recapture mechanismwhich permits the weft yarn, such as structural member 138, 138′ to bedispensed when the shuttle 130, 130′ is moved in the transversedirection. 142, 142′ through the shed but which recaptures the unusedweft yarn when the shuttle 130, 130′ is moved in the transversedirection in a sense opposite to the first direction, that is, when itis desired to recapture the structural member 138, 138′, as discussedabove with respect to the method. Such a recapture mechanism can includethe aforementioned frictional forces, eyelet and cantilevered portionshown in FIG. 18. Alternatively, with respect to FIG. 19, the recapturemechanism could include, for example, a motor 160 which is coupled tothe spool 134′ for rotational driving (for example, by a suitable pulleyarrangement as shown). The recapture mechanism can also include acontroller, such as a clutch 162 which is coupled to the motor so as toenable the rotational driving when it is desired to recapture the weftyarn, such as the structural member 138′. With reference to FIG. 19, forexample, the motor 160 could turn continuously and the clutch 162 couldbe engaged only when it was desired to recapture the yarn, such as thestructural member 138′. Motor 160 could be powered by a suitable battery164, or using fixed leads, sliding contacts, and the like.

Reference should now be had to FIG. 20, which depicts another embodimentof shuttle 130″ in accordance with the present invention. Also shown inFIG. 20 are a shuttle slide or batten 166 and a reed 168 of a loom.Batten 166 has a rack portion thereon; for illustrative convenience,only a small segment of the rack portion 170 is shown. Shuttle 130″includes a main body 132″ and a spool 134″ rotating about an axis 136″,similar to those described above. Main body 132″ includes a shuttle rack172, as is well known in the art, which can be used, via suitable gears,to drive the shuttle 130″. Shuttle 130″ further includes a pinionportion 174 which is mounted to the main body portion 132″ through anysuitable means, such as bearings (not shown) and which is operativelyinterconnected with the spool 134″, for example, by being mounted onaxis 136″, so as to rotate the spool 134″ for recapture of the unusedweft yarn, such as the structural member 138″ upon engagement of thepinion 174 with the rack 170 of the batten 166. A suitable clutch orother control can be employed so that rack 170 of batten 166 only causespinion 174 to rotate spool 134″ when it is desired to recapture weftyarn such as structural member 138″. A suitable weft yarn guide 140 or140′, as shown above, could be adapted to the structure of FIG. 20, butis not shown for purposes of illustrative simplicity.

Reference should now be had to FIG. 21 which depicts yet anotherembodiment of shuttle 130′″ according to the present invention.Components similar to those in the preceding Figures have received thesame number, followed by a triple “prime.” As for the other embodiments,shuttle 130′″ includes a main body portion 132′″ adapted to move in atransverse direction through a shed formed of warp yarns on the loom.Also included is a spool 134′″ which is mounted to the main body portion132′″ and which has an axis 136′″ which is substantially perpendicularto the transverse direction in which the shuttle 130′″ moves and whichis substantially parallel to the warp yarns. The spool 134′″ is adaptedto store the weft yarn, such as structural member 138′″, and to dispensethe weft yarn in a direction generally parallel to the spool axis 136′″when the main body portion 132′″ moves through the shed. This embodimentis similar to the so-called “spinning reel” familiar to fishermen. Spool134′″ can be stationary about axis 136′″, or, if desired, can rotatethereabout, depending on twist properties which it is desired to impartto structural member 138′″. Also included is a weft yarn guide which issecured to the main body portion 132′″ and which is positioned toreceive the weft yarn, such as structural member 138′″, as it isdispensed from the spool 134′″. As shown in FIG. 21, the weft yarn guidecan simply be a slot 176 which is formed in the main body portion 132′″and which receives the structural member 138′″ (or other weft yarn). Itwill be appreciated that the guide, such as slot 176, guides the weftyarn 138′″ into a direction which is substantially parallel to thetransverse direction in which the main body portion 132′″ moves. In theembodiment shown in FIGS. 20 and 21, it is to be appreciated that themain body portion 132″, 132′″ rides in the corresponding grooves formedin the batten 166, 166′″. Although any of the embodiments can beemployed with any structural member desired, it is believed that theembodiment shown in FIG. 21 has special utility with structural membersformed on the mandrel shown in FIGS. 15A and 15B.

Any suitable type of loom can be employed using the inventive shuttlesof the present invention. The warp yarn can be tensioned, for example,using the so-called drop-weight system of let-off, as is known in theart.

Attention should now be given to FIG. 22 which depicts a typical loomset up to manufacture products according to the present invention usingmethods according to the present invention. The loom, designatedgenerally as 200, weaves fabric in a direction indicated by arrow 202.Loom 200 includes a beam strap 204, warp beam 206, let-off brackets 208and warp tension weights 210, as known in the art. A suitable whip roll212, warp sheet 214, lease rods 216, heddle 218 and lingoe 220 are alsoshown. A warp shed 222 is depicted. A raised harness, suitable fordisplacing warp yarns as discussed above, is shown at 224. A breast beamis depicted at 226 and a take up roll is shown at 228. First and secondshuttles 230, 232 ride in batten 234, one above the other. One of theshuttles 230, 232 can be used for the ordinary weft yarns, while anotherof the shuttles 230, 232 can be used for the stent or structuralmembers, as discussed above. For the composite type embodiments, wheremultiple structural or stent members are used, additional shuttles canbe added as required.

Diameters of tubular stent/graft structures, for medical applications,according to the present invention can range from about 2 mm to about 50mm, although these dimensions are exemplary and should not be taken aslimiting. Larger diameters can be made for industrial applications, asdesired. Four harnesses 224 can be used to weave a simple double clothfabric tube. Additional harnesses can be used to control interweaving. Arapier loom can be used for weaving flat fabrics.

EXAMPLE

Tubular grafts, in accordance with the present invention, were preparedin the configuration shown in FIG. 1. The textile graft 12 was a groundweave plain lattice structure. The warp ground was 50/68 microdeniertexturized unshrunk polyester. Six stent-securing interweave warp yarnswere employed at each interweave point; these were two-plied yarns madefrom two individual 50/68 microdenier 8z texturized unshrunk polyesteryarns. The fill yarn was 50/68 microdenier 8z texturized unshrunkpolyester. The weave density for the finished fabric was 100 ends perinch, 118 picks per inch. The tubular graft 12 had a Griege insidediameter of 19 mm and a finished inside diameter of 18 mm.

The wire stent material was 0.011 inch (0.28 mm) diameter as-drawnNitinol shaped in a sinusoidal pattern using an aluminum mandrel of thetype shown in FIGS. 15A and 15B. The Nitinol shaping temperature wasabout 500 to about 560 degrees C. with dwell times ranging from about 1to about 5 minutes. A shaping temperature of 540 degrees C. was found tobe preferable.

Eight interweave points were spaced equally about the circumference ofthe graft and were repeated axially as needed. A helix angle of about 83degrees was employed as defined in FIG. 3 for the stent member globalaxis. Eight pick yarns separated each interweave point.

The radial force which can be developed and the ability to self-supportcan be controlled by varying the helix angle and wire diameter.Increasing either or both of these parameters increases the amount ofradial force. Reduced microdenier yarn twist can result in a denser,less permeable fabric.

After weaving, the stent/graft structure with interwoven wire wasscoured to remove any possible contamination from weaving and yarnsizing. The structure was then loaded on a cylindrical mandrel and heatset in a convection oven for 30 minutes at 130 degrees C. Heat settingresults in a three-dimensional shape-retaining fabric, but does notchange the elastic properties of the stent member. The dimensions,materials and other parameters set forth in the preceding example arethose currently believed preferable, but should not be taken aslimiting. For example, it is presently believed that 30 Denier yarns mayprove desirable for some medical applications.

While there have been described what are presently believed to be thepreferred embodiments of the invention, those skilled in the art willrealize that various changes and modifications may be made to theinvention without departing from the spirit of the invention, and it isintended to claim all such changes and modifications as fall within thescope of the invention.

What is claimed is:
 1. A method of forming a textile with an undulatingwire member therein, said method comprising the steps of: (a) forming awire exhibiting shape memory behavior into an undulating wire member;(b) training said wire to remember its shape while it is formed intosaid undulating wire member; (c) causing said undulating wire member tostraighten by undergoing a shape-memory transformation, therebyproducing a straightened wire with a memory of an undulating shape; (d)securing said straightened wire with said memory of said undulatingshape into a conventional textile; and (e) causing said straightenedwire to undergo a shape memory transformation back to its rememberedundulating shape.
 2. The method of claim 1, wherein step (a) comprises:(a-1) providing a flat mandrel with a first series of pins spacedsubstantially equiangularly at a first radius with a spacing angle θ anda second series of pins spaced substantially equiangularly at a secondradius with said spacing angle θ, said first and second series of pinsbeing substantially θ/2 out of phase; and (a-2) winding said wire in aninterlaced fashion about said pins to produce said undulating wiremember.
 3. The method of claim 1, wherein step (a) comprises: (a-1)providing a cylindrical mandrel with a first series of pins spacedsubstantially equiangularly, with a spacing angle γ, along a firsthelical path, and a second series of pins spaced substantiallyequiangularly, with said spacing and angle γ, along a second helicalpath which has an identical helix angle to said first helical path andwhich is displaced axially a predetermined distance therefrom, saidfirst and second series of pins being substantially γ/2 out of phasewhen viewed along an axis of said cylindrical mandrel; and (a-2) windingsaid wire in an interlaced fashion about said pins to produce saidundulating wire member.